To do Study functions of each cell understand diagram 6 12 6 13 6 15 6 17 Ch 6 Cells 6 1 biologists use microscopes and the tools of biochemistry to study cells 1 3 important factors in microscopy are magnification resolution and contrast 2 Cytology study of cell structure 3 Cell Fractionation takes cells apart and separates major organelles from each other a Used to isolate cell components based on size and density how we found site of cellular respiration Photosynthesis Cellular Respiration Location Mitochondria 4 Organelles the membrane enclosed structures within eukaryotic cells a Seen in detail by electron microscope EM which focuses a beam of electrons through the specimen or onto its surface 6 2 Eukaryotic cells have internal membranes that compartmentalize their functions 1 Cells basic structure and functional unit of every organism a Types prokaryotic and eukaryotic b They share these features i Bounded by a selective barrier called plasma membrane 1 Selective barrier allows passage of enough Oxygen nutrients and wastes to service the cell ii Cytosol cytoplasm 1 Cytosol A semifluid jelly like substance in which subcellular components are suspended 2 Cytoplasm interior of either type of cell iii Have chromosomes carry genes in DNA form iv Have ribosomes make proteins Prokaryotic Eukaryotic Before nucleus True nucleus Found in Bacteria archaea Protists fungi animals plants Location of DNA In nucleoid lack In nucleus nucleus Bounded by a double Not membrane membrane that enclosed compartmentalizes cellular functions Size Bacteria Larger mycoplasmas are 10 100 micrometers the smallest in diameter Regular bacteria 1 10 micrometers in diameter 10 X mycoplasmas Cytoplasm cytosol Region between nucleus and plasma membrane Other Has a specific number of chromosomes Human cell has 46 in the nucleus and 23 sex cell 2 As a cell increases in size its volume grows proportionately more than its surface area a Smaller object has a greater ratio of surface area to volume 3 Larger organisms DO NOT have larger cells they have more cells a Microvilli increase surface area with an appreciable increase in volume Eukaryotic cell 1 Extensive internal membranes that divide the cell into compartments organelles 2 Eukaryotic cell metabolism plasma membrane and organelle a Participate directly because enzymes built right in cell 3 Basic fabric of most biological membranes double layer of phospholipids and other lipids a Proteins embedded in lipid bi layer 4 Plant and animal cells are different even though they are eukaryotic look at pictures a Both have a nucleus ER Golgi apparatus and mitochondria b Chloroplasts only in photosynthetic eukaryotes 6 3 The Eukaryotic cell s genetic instructions DNA are housed in the nucleus and carried out by the ribosomes 1 2 3 4 Nucleus house of DNA Ribosomes use information from DNA to make proteins Nucleus contains most of the genes in the eukaryotic cell Nuclear Pore Envelope a Nuclear envelope encloses the nucleus separating its contents from the cytoplasm i Double membrane ii Each membrane has a lipid bi layer with certain proteins iii Pore structures perforate the envelope b Nuclear Pore at the lip of pore inner outer membranes of the nuclear envelops are continuous i Protein complex lines each pore and regulates the entering and exiting of proteins RNAs and large macromolecules ii Nuclear lamina nuclear side of envelope is lined with this 5 Nuclear lamina netlike array of protein filaments that maintain the shape of the nucleus by mechanically supporting nuclear envelope a Evidence of nuclear matrix help organize genetic material to function properly made of protein fibers 6 In nucleus the DNA is organized into discrete units called chromosomes a Chromosomes carry the genetic information b Each chromosome has one long DNA molecule with many proteins c Chromatin complex of DNA and proteins making up chromosomes Prokaryotic cell 1 Nucleolus a mass of densely stained granules and fibers adjoining part of the chromatin a Ribosomal RNA rRNA is synthesized here from the instructions of DNA all happening in nucleolus b Here proteins imported from the cytoplasm are assembled with rRNA into subunits of ribosomes small large c Subunits then exit the nucleus through the nuclear pores to the cytoplasm d Where a small and large subunit combine to make into a ribosome e Can be 2 or more nucleoli depending on stage in reproductive cycle and species 2 Nucleus directs protein synthesis by synthesizing messenger RNA mRNA according to instructions from DNA mRNA goes to cytoplasm via nuclear pores Ribosomes translate the mRNA s genetic message into primary structure of a polypeptide Ribosome protein factories 1 Ribosomes complexes made of ribosomal RNA rRNA and protein carry out protein synthesis 2 Large rate of protein synthesis large rate of ribosomes 3 Build proteins in 2 cytoplasmic places a Free ribosomes suspended in cytosol i Most proteins that function in the cytosol such as actin or in the nucleus such as DNA polymerase are synthesized made by free ribosomes b Bound ribosomes attached to the outside of the ER or nuclear envelope i Proteins that function within the endomembrane system such as lysosomal enzymes or those that are destined for secretion from the cell such as insulin are synthesized by bound ribosomes ii Bound ER proteins lysosomal enzyme insulin iii So they can be packaged within certain organelles i e Lysosomes iv As a protein destined for the endomembrane system is being synthesized by a ribosome the first amino acids in the growing polypeptide chain act as a signal sequence That signal sequence ensures that the ribosome binds to the outer membrane of the ER and that the protein enters the ER lumen 4 Nucleic acids cells info molecules DNA RNA a DNA carries the info Genes for building proteins b RNA intermediary in protein making translated to primary structure c Eukaryotic DNA to mRNA mRNA leaves nucleus and gives message to ribosomes message is translated by ribosomes into sequence of amino acids linked to make polypeptide 6 4 The Endomembrane System regulates protein traffic and performs metabolic functions in the cell I Endomembrane system nuclear envelope endoplasmic reticulum Golgi apparatus lysosomes various kinds of vesicles and vacuoles and the plasma membrane II Tasks include a Synthesis of proteins b Transport of proteins into membranes organelles or out of cell c Metabolism and movement of lipids d Detoxification of poisons III Vesicles